Parasitism of stink bugs by native parasitoids in Nebraska

This study investigated the parasitoid complex of stink bug (Hemiptera: Pentatomidae) in Nebraska. Three locations across eastern Nebraska were sampled for eggs, nymphs and adults. In adults and nymphs, parasitism was determined by the presence of dipteran egg and/or emergence of puparium. Two tachinid flies; Euthera and Cylindromyia species emerged from adult stink bugs. Out of more than 3000 adults examined in three years, only 49 were parasitized (~1.5%). Total number of dipteran eggs recorded was 63, with some individuals carrying multiple eggs. Approximately 60% of egg allocation was on the ventral side of hosts'  abdomen, thorax and limbs. Of the 21 species of stink bug collected during this survey, adult parasitism was observed in only Euschistus variolarius, Thyanta custator, Chinavia hilaris and Podisus maculiventris. The most parasitized species was T. custator, making up ~57%. Nymph parasitism was not observed in this study. To check for the presence of egg parasitoids, eggs were randomly collected from the field and placed in a growth chamber [25 ± 1°C, 75 ± 5% RH and 14:10 h (L:D)] until eclosion. Sentinel eggs that were deployed in the field for 72 hours were also observed for parasitism. The species of parasitoid, parasitism and emergence rates were recorded. Telenomus podisi Ashmead (Hymenoptera: Platygastridae) was the only parasitoid that emerged from all parasitized eggs. Mean parasitism was ~90% in feral eggs and ~75% in sentinel eggs. Results suggest that parasitoids are a viable option for stink bug control in Nebraska.